[Hallc_running] [New Logentry] Sunday RC update for Hall C

mack at jlab.org mack at jlab.org
Sun Jun 23 13:25:01 EDT 2019

Logentry Text:
We had a few things we could do Sat day thru Sun owl with a low power target as per Mark's run plan at https://logbooks.jlab.org/entry/3691923 . 

On Saturday day shift, after the 1 GeV/c sieve measurements finished, there was a beam energy measurement. Then at Mark's suggestion we asked the MCC to try for higher beam current with the target out but raster on. Unfortunately, the maximum stable current was only 25 muA* , but we did a bcm calibration to check that system is working. (From Deb's log entry at https://logbooks.jlab.org/entry/3692338 it looks like this was even less useful than we had hoped.) Swing shift began a detailed SHMS pointing scan which Sunday owl shift completed. Owl shift then did a calibration of the BPMs using harps scans. (Scanning the beam in a box pattern permits untangling the BPM gains and offsets.) Florian called me to say he had run out of program, so we asked the MCC to take beam away at 08:00 and cancelled shifts up until Monday day. A shout out to Gabi for driving 3+ hours for his day shift only to be sent home. :( 

We've left Hall C in a mostly ready state: the WC HV is off (just cuz), but all magnets are ON, and angles are where the owl crew left them. The hall is in power permit to discourage eco-tourism. 

No RC meeting today. I want to get an update on the ESR on Monday morning before we decide what angles and momenta to set the spectrometers.  

*We're going to need several times higher current for the summer program. But our priority this weekend was "opportunistic", and of course the push to higher current was increasing the trip rate in scheduled halls A and B. So it's all good. 


This is a plain text email for clients that cannot display HTML.  The full logentry can be found online at https://logbooks.jlab.org/entry/3692489
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